Officials of P.I. Properties Inc., the mid-1970s owner of the dilapidated Clifton Terrace apartments, regularly used the security guards they hired to work at the complex to run personal errands, cash checks and do construction work elsewhere, three former guards testified yesterday.

Curtis Clark, Peter Reed and Samuel McMickle all told a federal court jury hearing the fraud and conspiracy case against P.I. Properties' former president, Mary Treadwell, that they performed construction work on housing rehabilitation projects being done by another Treadwell-operated firm, Sticks and Stones Inc.

In addition, the three said that P.I. Properties' general manager, Robert E. Lee, asked them regularly to drive to local banks to cash checks for him. Reed and McMickle said Joan M. Booth, Treadwell's sister and Clifton Terrace's project manager, almost daily asked them to drive her daughter to and from school.

McMickle said that he occasionally served as Treadwell's personal bodyguard and that on one occasion he went to Treadwell's home to ask Marion Barry, her husband at the time, to leave the home because of a dispute the couple was having.

Barry, divorced from Treadwell in 1977 and now D.C. mayor, has not been implicated in any wrongdoing in the case against Treadwell.

Prosecutors presented yesterday's testimony in an attempt to show how Treadwell, Lee and Booth used the private security force they created, known as Pride Economic Enterprises Special Police, for purposes other than its original mandate to provide security for Clifton Terrace's tenants.

Treadwell is accused of using P.I. Properties, a real estate affiliate of the defunct Youth Pride self-help organization, to defraud the federal government and Clifton Terrace's impoverished residents of thousands of dollars to enrich herself. Lee and Booth have both pleaded guilty to conspiracy and other charges in the case and Lee likely will be called as a witness against Treadwell next week.

Clark, Clifton Terrace's director of security from 1975 until he was fired in 1977 when he started complaining to federal housing officials about P.I. Properties' management of the project, said that no extra security guards were hired to patrol the Northwest Washington complex while the guards were dispatched to run errands or work elsewhere.

John W. Nields, Treadwell's court-appointed defense attorney, attempted to discredit Clark's and McMickle's courtroom testimony by suggesting to both of them that they had changed their stories from the time they were first interviewed by investigators or testified before a federal grand jury.

But both adamantly resisted Nields' attempts to get them to admit that they had lied in their previous statements.

At one point, McMickle looked sternly at the defense attorney and told him, "You're the one that's lying."

In other testimony, Joanne Thomas, a Department of Housing and Urban Development contract specialist in the mid-1970s, testified that Treadwell made it clear she wanted to hire the newly created special police force to do the security work at Clifton Terrace in the spring of 1975, a time when P.I. Properties managed but did not yet own Clifton Terrace.

Thomas said that Treadwell objected to the use of Guardian Security Agency, the only firm that bid for the work under a HUD contract, because the company is white-owned. Thomas testified that a HUD contracting officer, William W. Belcher, eventually rejected Guardian's bid and approved a negotiated contract with the Pride special police organization.

At the time, according to earlier testimony in the trial, Booth, at Treadwell's request, was dating Belcher "because it would be beneficial to the company."